Ultimately, Alessandro Schopf's injury-time goal handed Schalke a 1-0 win in the Group D tie at Veltins-Arena, sealing their place in the next round of the competition.
In all, his four games consist of two league outings, one German Cup appearance, and Tuesday's Champions League fixture.
Baba's lack of game time at Schalke has been due to a loss of form and match fitness following a long injury layoff.
While at Schalke on an initial one-year loan from Chelsea, the defender sustained an injury with Ghana at the 2017 Africa Cup of Nations.
Initially expected back in action after seven months, a series of relapses kept him in the treatment room until May this year when he played for Schalke as a second-half substitute on the final matchday of the 2017-18 Bundesliga season.
At the start of the current campaign, he looked ready to pick up from where he left off after starting the Royal Blues' first game in the German Cup and first two matches of the Bundesliga.
The September 2 meeting with Hertha, though, remained his last outing for Domenico Tedesco's outfit until the latest Champions League appearance.
His lack of game time has heightened reports about a premature termination of a follow-up 18-month loan deal from Chelsea in January.